Massive die-off of saiga antelopes

The saiga (Saiga tatarica, order Artiodactyla) is a rare nomadic antelope species that inhabits the steppes, semiarid deserts, and plains of central Asia. Its most strikingly distinctive feature is its large humped nose or proboscis, which hangs down over its mouth. Formerly found across southeastern Europe and much of Asia, this creature is listed as critically endangered by the International Union for Conservation of Nature (IUCN). The saiga has faced tremendous reductions in its numbers from habitat loss, land degradation, and competition for grazing grounds, but also particularly from hunting. Traditional Chinese medicine enthusiasts highly prize the horns of the male antelope for their supposed medicinal qualities; consequently, reckless demand has extirpated the saiga population in China and neighboring countries. Today, saigas inhabit Kazakhstan predominantly, but there are also lesser populations in Kalmykia (southwestern Russia) and western Mongolia, as well as herds that migrate through areas of Uzbekistan and Turkmenistan. The saiga population totaled more than a million between the 1970s and the early 1990s, but at present it has been reduced to possibly only 50,000 individuals. This huge, rapid die-off puts these unique animals at risk for complete extinction. See also: Antelope; Artiodactyla; Asia; Ecology;
Ecosystem; Endangered species; Extinction (biology); Population ecology

A mother saiga and her calf in Kalmykia, Russia. (Photo by Igor Shpilenok)

In the spring of 2015, and mostly over the course of just two weeks in May, approximately half of the world's saiga population was wiped out as the result of some unidentified disease. More than 210,000 saigas perished at this time, eliminating about 88% of the main population in Kazakhstan. The outbreak in 2015 followed similar die-offs that occurred in each of the years since 2010, although mortalities were previously much fewer. Investigators have been attempting to pinpoint the cause of these catastrophic incidents, with most scientists ascribing the massive die-offs to some combination of bacterial infection and other predisposing environmental factors (for example, colder winters and wetter springs resulting from climate change). Some leading possibilities include pasteurellosis, an infection that comprises a variety of diseases caused by the Pasteurella species, and conditions that include internal bleeding connected with toxins produced by Clostridium species. However, those bacterial species typically do not harm most saigas, so there must be additional triggers (likely environmental) that have aggressively weakened the immune systems of these animals. In most instances, the first animals to be affected and die are the females, which typically cluster in groups to calve their young. After the deaths of the adult females, the calves, which are too young to eat vegetation, succumb next. Still, the exact culprit remains a mystery, but one that needs to be solved quickly to ensure the viability of the species. See also: Climate modification; Clostridium; Environmental toxicology; Global climate change; Pasteurella; Pasteurellosis; Population viability; Virulence

To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.

Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.

About AccessScience

AccessScience provides the most accurate and trustworthy scientific information available.

Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 39 Nobel Prize winners.

Features

MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology

115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms

3000 biographies of notable scientific figures

MORE THAN 17,000 downloadable images and animations illustrating key topics

ENGAGING VIDEOS highlighting the life and work of award-winning scientists

SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research

LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information